<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>backdrop-filter interpolation</title>
    <link rel="help" href="https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty">
    <meta name="assert" content="Matching lists interpolate.">
    <script src="../../../resources/testharness.js"></script>
    <script src="../../../resources/testharnessreport.js"></script>
    <script src="../../../css/support/interpolation-testcommon.js"></script>
    <style>
      .parent {
        backdrop-filter: hue-rotate(30deg);
      }
      .target {
        display: inline-block;
        width: 50px;
        height: 50px;
        background-color: green;
        color: white;
        margin-right: 2px;
        backdrop-filter: hue-rotate(10deg);
      }
      .expected {
        margin-right: 20px;
      }
      .test {
        padding-bottom: 10px;
      }
    </style>
  </head>
  <body>
    <script>
      'use strict';

      test_interpolation({
        property: 'backdrop-filter',
        from: 'hue-rotate(0deg) blur(6px)',
        to: 'hue-rotate(180deg) blur(10px)'
      }, [
        {at: -0.5, expect: 'hue-rotate(-90deg) blur(4px)'},
        {at: 0, expect: 'hue-rotate(0deg) blur(6px)'},
        {at: 0.25, expect: 'hue-rotate(45deg) blur(7px)'},
        {at: 0.5, expect: 'hue-rotate(90deg) blur(8px)'},
        {at: 1, expect: 'hue-rotate(180deg) blur(10px)'},
        {at: 1.5, expect: 'hue-rotate(270deg) blur(12px)'}
      ]);

      // Matching lists with differing units:
      test_interpolation({
        property: 'backdrop-filter',
        from: 'hue-rotate(80deg) blur(6mm)',
        to: 'hue-rotate(100grad) blur(1cm)'
      }, [
        {at: -0.5, expect: 'hue-rotate(75deg) blur(4mm)'},
        {at: 0, expect: 'hue-rotate(80deg) blur(6mm)'},
        {at: 0.25, expect: 'hue-rotate(82.5deg) blur(7mm)'},
        {at: 0.5, expect: 'hue-rotate(85deg) blur(8mm)'},
        {at: 1, expect: 'hue-rotate(90deg) blur(10mm)'},
        {at: 1.5, expect: 'hue-rotate(95deg) blur(12mm)'}
      ]);

      test_interpolation({
        property: 'backdrop-filter',
        from: neutralKeyframe,
        to: 'hue-rotate(20deg)',
      }, [
        {at: -0.5, expect: 'hue-rotate(5deg)'},
        {at: 0, expect: 'hue-rotate(10deg)'},
        {at: 0.3, expect: 'hue-rotate(13deg)'},
        {at: 0.6, expect: 'hue-rotate(16deg)'},
        {at: 1, expect: 'hue-rotate(20deg)'},
        {at: 1.5, expect: 'hue-rotate(25deg)'},
      ]);

      test_interpolation({
        property: 'backdrop-filter',
        from: 'initial',
        to: 'hue-rotate(20deg)',
      }, [
        {at: -0.5, expect: 'hue-rotate(-10deg)'},
        {at: 0, expect: 'hue-rotate(0deg)'},
        {at: 0.3, expect: 'hue-rotate(6deg)'},
        {at: 0.6, expect: 'hue-rotate(12deg)'},
        {at: 1, expect: 'hue-rotate(20deg)'},
        {at: 1.5, expect: 'hue-rotate(30deg)'},
      ]);

      test_interpolation({
        property: 'backdrop-filter',
        from: 'inherit',
        to: 'hue-rotate(20deg)',
      }, [
        {at: -0.5, expect: 'hue-rotate(35deg)'},
        {at: 0, expect: 'hue-rotate(30deg)'},
        {at: 0.3, expect: 'hue-rotate(27deg)'},
        {at: 0.6, expect: 'hue-rotate(24deg)'},
        {at: 1, expect: 'hue-rotate(20deg)'},
        {at: 1.5, expect: 'hue-rotate(15deg)'},
      ]);

      test_interpolation({
        property: 'backdrop-filter',
        from: 'unset',
        to: 'hue-rotate(20deg)',
      }, [
        {at: -0.5, expect: 'hue-rotate(-10deg)'},
        {at: 0, expect: 'hue-rotate(0deg)'},
        {at: 0.3, expect: 'hue-rotate(6deg)'},
        {at: 0.6, expect: 'hue-rotate(12deg)'},
        {at: 1, expect: 'hue-rotate(20deg)'},
        {at: 1.5, expect: 'hue-rotate(30deg)'},
      ]);

      test_interpolation({
        property: 'backdrop-filter',
        from: 'none',
        to: 'hue-rotate(180deg)'
      }, [
        {at: -0.5, expect: 'hue-rotate(-90deg)'},
        {at: 0, expect: 'hue-rotate(0deg)'},
        {at: 0.25, expect: 'hue-rotate(45deg)'},
        {at: 0.5, expect: 'hue-rotate(90deg)'},
        {at: 1, expect: 'hue-rotate(180deg)'},
        {at: 1.5, expect: 'hue-rotate(270deg)'},
      ]);

      test_interpolation({
        property: 'backdrop-filter',
        from: 'hue-rotate(180deg)',
        to: 'none'
      }, [
        {at: -0.5, expect: 'hue-rotate(270deg)'},
        {at: 0, expect: 'hue-rotate(180deg)'},
        {at: 0.25, expect: 'hue-rotate(135deg)'},
        {at: 0.5, expect: 'hue-rotate(90deg)'},
        {at: 1, expect: 'hue-rotate(0deg)'},
        {at: 1.5, expect: 'hue-rotate(-90deg)'},
      ]);

      test_interpolation({
        property: 'backdrop-filter',
        from: 'drop-shadow(0px 0px 0px currentcolor)',
        to: 'drop-shadow(20px 10px green)'
      }, [
        {at: -1, expect: 'drop-shadow(-20px -10px white)'},
        {at: 0, expect: 'drop-shadow(0px 0px 0px currentcolor)'},
        {at: 0.5, expect: 'drop-shadow(10px 5px #80C080)'},
        {at: 1, expect: 'drop-shadow(20px 10px green)'},
        {at: 1.5, expect: 'drop-shadow(30px 15px #004100)'}
      ]);

      test_no_interpolation({
        property: 'backdrop-filter',
        from: 'url("#svgfilter")',
        to: 'blur(5px)',
      });

      test_interpolation({
        property: 'backdrop-filter',
        from: 'initial', // lacuna is 0
        to: 'sepia(1)'
      }, [
        {at: -1, expect: 'sepia(0)'}, // Negative values are not allowed.
        {at: 0, expect: 'sepia(0)'},
        {at: 0.5, expect: 'sepia(0.5)'},
        {at: 1, expect: 'sepia(1)'},
        {at: 1.5, expect: 'sepia(1)'} // Should clamp values to 1.
      ]);
    </script>
  </body>
</html>
